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README.md

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This is a thin c-api wrapper programmatically generated for the excellent C++ immediate mode gui Dear ImGui. All functions are programmatically wrapped except ImVector constructors and destructors. (Unless someone find a use case for them)(Now they exist for ImVector_ImWchar) Generated files are: cimgui.cpp, cimgui.h for C compilation. Also for helping in bindings creation, definitions.lua with function definition information and structs_and_enums.lua. This library is intended as a intermediate layer to be able to use Dear ImGui from other languages that can interface with C (like D - see D-binding)

History:

Initially cimgui was developed by Stephan Dilly as hand-written code but lately turned into an auto-generated version by sonoro1234 in order to keep up with imgui more easily (letting the user select the desired branch and commit)

Notes:

compilation

using generator

  • you will need LuaJIT (https://github.com/LuaJIT/LuaJIT.git better 2.1 branch) or precompiled for linux/macOS/windows in https://luapower.com/luajit/download
  • you can use also a C++ compiler for doing preprocessing: gcc (In windows MinGW-W64-builds for example), clang or cl (MSVC) or not use a compiler (experimental nocompiler option) at all. (this repo was done with gcc)
  • update imgui folder to the version you desire.
  • edit generator/generator.bat (or make a .sh version and please PR) to choose between gcc, clang, cl or nocompiler. Run it with gcc, clang or cl and LuaJIT on your PATH.
  • as a result some files are generated: cimgui.cpp and cimgui.h for compiling and some lua/json files with information about the binding: definitions.json with function info, structs_and_enums.json with struct and enum info, impl_definitions.json with functions from the implementations info.

generate binding

definitions description

  • It is a collection in which key is the cimgui name that would result without overloadings and the value is an array of overloadings (may be only one overloading)
  • Each overloading is a collection. Some relevant keys and values are:
    • stname : the name of the struct the function belongs to (may be ImGui if it is top level in ImGui namespace)
    • ov_cimguiname : the overloaded cimgui name (if absent it would be taken from cimguiname)
    • cimguiname : the name without overloading (this should be used if there is not ov_cimguiname)
    • ret : the return type
    • argsT : an array of collections (each one with type: argument type and name: the argument name)
    • args : a string of argsT concatenated and separated by commas
    • call_args : a string with the argument names separated by commas for calling imgui function
    • defaults : a collection in which key is argument name and value is the default value.
    • manual : will be true if this function is hand-written (not generated)
    • isvararg : is setted if some argument is a vararg
    • constructor : is setted if the function is a constructor for a class
    • destructor : is setted if the functions is a destructor for a class
    • nonUDT : if present can be 1 or 2 (explained meaning in usage) if return type was a user defined type

structs_and_enums description

  • Is is a collection with two items:
    • under key enums we get the enums collection in which each key is the enum tagname and the value is an array of the ordered values represented as a collection with keys
      • name : the name of this enum value
      • value : the C string
      • calc_value : the numeric value corresponding to value
    • under key structs we get the structs collection in which the key is the struct name and the value is an array of the struct members. Each one given as a collection with keys
      • type : the type of the struct member
      • template_type : if type has a template argument (as ImVector) here will be
      • name : the name of the struct member

usage

  • use whatever method is in ImGui c++ namespace in the original imgui.h by prepending ig
  • methods have the same parameter list and return values (where possible)
  • functions that belong to a struct have an extra first argument with a pointer to the struct.
  • where a function returns UDT (user defined type) by value some compilers complain so another function with the name function_name_nonUDT is generated accepting a pointer to the UDT type as the first argument.
  • also is generated function_name_nonUDT2 which instead of returning the UDT type returns a simple version (without functions) called UDTType_Simple (ImVec2_Simple for ImVec2)

example bindings based on cimgui